Fuel and damper control combination



Nov. 15, 1949 v. J. EVANS FUEL AND DAMPER CONTROL COMBINATION Filed Jan. 11, 1946 INVENTOR.

Patented Nov. 15, 1949 UNITED FUEL AND DAMPER CONTROL COMBINATION Vincent J. Evans, Lakewood, hio,,.assignor to:

Grand Industries, Inc., Cleveland,.0l1io,a corporation of Ohio Application Januaryll, 1946,; SerialN 0.1640562 7 Claims.

This invention relates to a device for controlling the admission of fuel to a burner and for controlling a damper of a compartment in which the burner is located in accordance with the amount of fuel admitted to the burner.

One of the principal objects of the present invention is to provide a damper control,,for a burner and damper combination, which is operated in response to the differential in pressure of the fluid fuel supply line and the pressure of the fuel delivered to the burner.

Another object is. to provide a control for a burner and damper combination which is safe and accurate in operation and in which the possibility of the damper remaining closed when the burner is receiving asupply of fuel is eliminated or reduced to a minimum.

Another object is to provide, in an oven with a burner and damper, a control which operates in a .manner to conserve the heat in the oven more efficiently than heretofore.

A specific object is to provide in an oven having a burner and a vent a thermostaticzcontrol for the burner responsive to the oven heat and a damper for the vent controlled by and in accordance with the fuel delivery to the burner whereby not only is the escape of heat from the oven reduced but also adequate venting of theoven for discharge of the products of combustion or unburned gases is obtained.

Other objects and advantages will become ape parent from the following description wherein reference is made to the drawings, in which The drawing is a schematic illustration. of an embodiment of the invention, showing a vertical sectional view through a portion of an oven with the device of the present invention installed, the damper control of the present invention being shown in section, the fuel supply control being shown on a larger scale in section, and the burner being shown in plan.

For the purposes of illustration, the invention is shown as applied to a gas fired burner in an oven of a gas range, its use with other types of fluid fuel and for other purposes being readily apparent from the illustrative example.

- In ovens of gas ranges, it is desirable tocontrol the venting of the oven either for the admission of secondary air or for the exhaust of the products of combustion, or both, in accordance with the amount of fuel delivered to theburner so as to maintain efiicient'combustion and to conserve the heat supplied. Inthe illustrative example, the exhaust vent damper is shown as controlled by the device of the present invention, the control of aninlet vent damper or two dampers, one for ex.- haust and one for the inlet, being readily apparent from the illustrative example.

Referring to the drawing, the oven l is provided with a suitable exhaust vent 2 which is controlled by a damper Sand discharges into a suita- I ble exhaust stack 4 located at the. rear of the range. Theoven is heated by a suitable burner 5, thesupply of gas to which is controlled by a suitable control 1. For purposes of illustration the burner 5 is shown as a dual burner such as described in my copending application, Serial No. 640,561, filed January 11, 1946, having a low heat burner portion .8 and a high heat burner portion 8, the portions having independent mixing bells it] and H, respectively. Gas is supplied-to the burner portion 8 through a suitable pipe [2 and ,to the burnerportion 9 through a suitable pipe is, aplot 14 being provided and connected to the line !2 for assisting in lighting the burners 5.

The pipes l2 and I3 are connected with the control device 7 which, in turn, is connected to the main gas supply line H. The control device, which is more fully described in my above identitled copending application, comprises a stop cock. plug .Idhaving suitable ports I6 and I! and c'ncumferential grooves l8 and i9 which are adapted for registry in: one rotated position of the plug it with suitable ports 20 and 2! which, in turn, are connected to the pipes l2 and I3, respectively. By-pass ducts 22 and 23, adjustable by suitable needle valves 24 and 25, respectively, are provided in the device for admitting predetermined adjusted amounts ofby-passed gas'to the burner portions 8 and 9, respectively by way of the grooves 16 and H.

A thermostatically operated valve'plug 261s provided and operated by a single thermostatic bellows 2: responsive to the heat applied to the expansible fluid vial 28 located in the oven. The valve plug 25 is operable to open and close a supply of gas to the burners independently of the bypass ducts 22 and 23.

The plug l5 and thermostatic valve plug 26 are connected so that upon rotation of the plug [5 the thermostat is adjusted for the temperature desired in the oven. The valve plug 261s arranged to be opened by the plug IE only after rotation of the plug l5 fromiclosed toward open position toa position beyond which the by-passes have become already operative. Thereaften-the thermostatic bellows 2! controls the supplyof gas to the burners. However, any other type of burner and any manual, time, or thermostatically controlled valve' can be provided for admitting controlled amounts of gas from the supply line M to the burner 5 regardless of whether-the burner 5 is a dual or single burner.

As a safety precaution the damper 3 preferably is provided with a bleeder hole 28;so that when the damper is; fully closed at least some escape vent for gases is permitted.

In order to operate the damper in'response to the amount of fuel admitted to the. burn r 5, a differential 'fiuid pressure operated means 2951s provided. A suitable means for this purpose may comprise a hollow body which is divided by a diaphragm 3| into two sealed compartments. The diaphragm 3| is operatively connected by a suitable push rod 32 to the damper 3, the rod 32 being pivotally connected to the damper by a pivot 33 and the damper being pivotally supported by a pivot 34 in position to swing from open to closed positions with respect to the vent 2. A spring is provided on one side of the diaphragm and through the medium of the diaphragm 3| and rod 32, urges the damper 3 to an open position, as illustrated, the spring being adequate to move the damper to a fully opened position when the pressures on the opposite sides of the diaphragm are equalized or in a predetermined balance.

The differential fluid pressure device is connected at the side of the diaphragm opposite from the spring 35 with the main ga supply line 14 by means of a suitable pipe 36. The other side of the fluid pressure operated device, which is the side on which the spring is positioned, is connected by a suitable pipe 3! to the fuel supply admitted by the control device l to the burner 5. Since the vent 2B is adequate to take care of a low heat such as might be supplied by the burner portion 3, the temperature control is made to operate in response to the gas supplied to the 7 high heat burner 9 which, for the purposes of the present damper control, may be considered as the only burner provided in the oven.

As described in my said copending application, the burner portions 8 and 9 have the usual throttling nozzles 33 and 39, respectively, so that a the gas admitted to the pipe 13 from the device I is maintained at a pressure less than that of the supply line H and is varied in response to the operation of the thermostatic valve or other control valve. Thus the pressure supplied by the line 33 is in opposition to the pressure supplied by the lines 3'! and l3.v Accordingly, the more gas that is admitted to the burner 5 through the line l3, the more nearly does the pressure in the line 3! approach the pressure in the line 36. As mentioned, the spring 35 is so selected that it urges the damper 3 to open position. However, the full line pressure from the main line I l, when applied to the diaphragm 3| in opposition to the spring 35, is sufficient to move the diaphragm against the resistance of the spring 35 and close the damper. On the other hand, as more pressure is admitted through the line 3?, due to the admission of a greater amount of fuel to the burner 5 through the line l3, the pressure on the same side of the diaphragm as the spring increases and partially balances the pressure from the line 36. The more nearly this balance is approached, the less is the opposition to the spring and resistance to movement of the damper to open position by the spring 35. The spring preferably is so selected that when a full supply of gas is admitted to the burner 5, the differential in pressure exerted on one side of the diaphragm by the spring and by the gas pressure in the line 31 overbalances the gas pressure exerted on the opposite side of the diaphragm by gas pressure in the line 36 and thus opens the damper. As the flow of fuel to the burner is reduced, obviously there is a less total overbalance in the opening direction of the damper and therefore the damper is moved toward closed position by the pressure from the line 36 in opposition to the spring 35. The amount of closing movement is in a direct proportional relationship to 4 the reduction of the amount of fuel supplied to the burner 5.

It is apparent from the foregoing description that since the spring urges the damper to open position and is adequate to open it, any leakage or cut-off or stoppage in the line 36 would result in the damper remaining open, thus providing a safety feature against such hazards. Furthermore, in event of leakage of the diaphragm, the fluid pressure on opposite sides thereof will tend to balance and the spring 35 then will open the damper 3.

While I have described the invention as employing a differential pressure means of the diaphragm type, obviously other types of differential fluid pressure operated means may be employed and similarly connected. The present type has the advantages that the gas itself operates directly on the moving part of the differential fluid pressure operated means rather than through the medium of interposed liquids, plungers and the like. Furthermore, the spring in the present illustration has been located within the differential pressure means so that it, in effect, forms a part thereof, but it can as readily be located outside except for the loss of protection to it when in an exposed position. If desired, the spring 35 may be omitted and the damper 3 made sufliciently heavy or overbalanced to open by gravity in which case gravity is part of the means opposing closure of the damper.

It is apparent that though the push rod 32 is shown as connected to an exhaust damper for control thereof, it could as readily be connected to an inlet damper or, by a suitable link or lever, connected to both an inlet damper as Well as the exhaust damper, thus controllin th secondary air inlet vent or both the inlet and exhaust vents. However, the control of the exhaust vent usually controls sumciently well the inflow of secondary air through the usual oven air intake ports or vents.

I claim:

1. A control device for a compartment having a burner therein and a vent, comprising a conduit for conducting fluid fuel to the burner, a thermostatic valve adapted for connection on its inlet side to a source of fluid fuel and connected on its discharge side to said conduit for admitting fuel, and for varying the amount of fuel admitted, to the burner, a damper adapted for cooperation with said vent, differential fluid pressure means operatively connected to the damper and holding the damper in closed position when the fluid pressure on the inlet side of said fluid pressure means is greater than the total force applied on the opposite side, means for operatively connecting the inlet side of the differential fluid pressure means to the fuel supply on the inlet side of the valve, and means for operatively connecting the opposite side of th differential fluid pressure means to the burner fuel supply on the discharge side of the valve.

2. A control device for a compartment having a burner therein and an exhaust vent, comprising a variable flow thermostatic valve adapted for connection on its inlet side to a fluid fuel supply line, means for connecting the valve on its outlet side to the burner, a damper for cooperation With said vent, differential pressure operated means operatively connected to the damper and including resilient means normally urging the damper to open position and holding the damper in open position when the fluid pressure on the opposite sides of the differential fluid pressure operated means is in a predetermined balance, means connecting one side of the fluid pressure operated means to the inlet side of the valve for effecting operation of the fluid pressure operated means by line pressure in opposition to the resilient means for moving the damper to closed position, additional means connecting the other side of the fluid pressure operated means to the fuel supply at the outlet side of the valve for changing the balance, whereby the damper is operated in accordance with the flow of fuel to the burner.

3. A control device for a compartment having a fluid fuel burner therein and a vent, comprising a variable flow fuel control valve adapted for connection at its inlet side to a fluid fuel supply line and for connection at its outlet side to the burner, a damper adapted for cooperation with the vent, a sealed body, a diaphragm divid ing the body into separate compartments, means operatively connecting the damper and diaphragm for movement of the damper thereby to a closed position, resilient means urging the damper to open position, means connecting the body at one side of the diaphragm with the inlet side of the valve for urging the damper to closed position against the resistance of the resilient means, and means connecting the body at the opposite side of the diaphragm with the outlet side of the valve whereby the damper is opened in the direct ratio to the amount of fuel admitted to the burner.

4. In combination, a compartment having a vent, a burner therein, a variable flow valve adapted for connection at its inlet side to a source of fluid fuel, means connecting the outlet side of the valve to the burner, a damper cooperable with the vent, differential fluid pressure operated means connected to the damper and operable for movin the damper to closed position when the fluid pressure on opposite sides of the fluid pressure operated means is in a predetermined unbalanced condition, means for connecting one side of the differential fluid pressure operated means to said source on the inlet side of the valve for urging the damper to closed position, means connecting the other side of the differential pressure operated means to the fuel supply to the burner on the discharge side of the valve, and means urging the damper to open position in opposition to the presser on the differential fluid pressure operated means from the inlet side of the valve.

5. In combination, a compartment having a vent, a pair of burners therein, one of said burners being larger than the other, a thermostatic valve adapted for connection at its inlet side to a source of fluid fuel, means connecting the outlet side of the valve to the larger burner, a damper cooperable with the vent, differential fluid pressure operated means operable for moving the damper to closed position when the fluid pressure on opposite sides thereof is in a predetermined unbalanced condition, means for connecting one side of the differential fluid pressure operated means to said source on the inlet side of the valve for urging the damper to closed position, means connecting the other side of the differential fluid pressure operated means to the fuel supply to the larger burner on the discharge side of the valve, means operatively connecting the differential fluid pressure operated means to the damper, means urging the damper to open position in opposition to the pressure on the differential fluid pressure operated means from the inlet side of the valve, a stop cock interposed between the thermostatic valve and the burners, means connecting the stop cock and thermostatic valve for setting and adjustment of the thermostatic valve by rotation of the stop cock in the opening direction, and means in the stop cock for admitting fuel to the smaller burner in advance of the position in which the thermostatic valve is operable to admit fuel to the larger burner.

6. A control device for a compartment having a fluid fuel burner therein, a vent and a damper for said vent, comprising a variable flow thermostatic control valve adapted for operation in response to heat from the burner, opening means connectable to the damper and operable when connected for normally urging the damper to open position, means for connecting the inlet side of the thermostatic valve to a fluid fuel supply line, means for connecting the discharge side of the valve to the burner, differential fluid pressure operated means connected to the opening means and operable in opposition to said opening means, means connecting one side of the differential fluid pressure means to the inlet side of the valve for opposing the opening means and closing the damper, means connecting the other side of the fluid pressure operated means and the discharge side of the valve for admitting gas to the said other side of the differential fluid pressure operated means at a pressure proportional to that supplied to the burners.

7. In combination, a variable flow fluid fuel control valve adapted for connection at its inlet side to a fuel supply line and adapted for connection at its outlet side to a fuel burner, a damper adapted for use with a vent of a com partment, differential fluid pressure operated means connected to the damper for movin the damper toward open and closed positions, and means connecting opposite sides of the differential fluid pressure operated means to opposite sides of the valve, respectively, so that, when the combination and a burner under the control of the valve are installed for use with a compartment, the damper becomes responsive to the differential in the pressure of said supply line and the pressure of the fuel to be supplied to the burner from the valve and is opened and closed whereby in proportion to the amount of fuel supplied to the burner.

VINCENT J. EVANS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,495,437 Powers May 27, 1924 1,977,216 Unger Oct. 16, 1934 2,051,401 Winterstein Aug. 18, 1936 2,184,983 Tornquist Dec. 26, 1939 2,241,661 Furlong May 13, 1941 FOREIGN PATENTS Number Country Date 545,766 Germany Mar. 5, 1932 

